1206.1213 (Ramesh Narayan et al.)

GRMHD Simulations of Magnetized Advection Dominated Accretion on a Non-Spinning Black Hole: Outflows and Convection    [PDF]

Ramesh Narayan, Aleksander Sadowski, Robert F. Penna, Akshay K. Kulkarni

We present results from two long-duration GRMHD simulations of an advection-dominated accretion flow around a non-spinning black hole. The first simulation was designed to avoid significant accumulation of magnetic flux around the black hole. This simulation was run for a time of 200,000GM/c^3 and achieved inflow equilibrium out to a radius \sim 100GM/c^2. Up to this radius, we do not see significant mass outflow. We estimate that, if at all, only at radii \gsim 300GM/c^2 does the mass outflow rate (\dot{M}_{\rm out}) exceed the net mass inflow rate into the black hole (\dot{M}_{\rm BH}). The second simulation was designed to achieve substantial magnetic flux accumulation around the black hole in a magnetically arrested disc. This simulation was run for a time of only 100,000GM/c^3. Nevertheless, because the mean radial velocity was several times larger than in the first simulation, it reached inflow equilibrium out to a radius \sim 200GM/c^2. The mass outflow rate is larger, though even in this case, $\dot{M}_{\rm out}$ exceeds \dot{M}_{\rm BH} only at radii well above 100GM/c^2. Since the mass outflow rates in the two simulations do not show robust convergence with time, it is possible that the true rates are lower than our estimates. Neither simulation shows strong evidence for convection. The effect of black hole spin remains to be explored.

View original: http://arxiv.org/abs/1206.1213